Turbulent Flows

Phenomenological and theoretical introduction to turbulence and the scales found within it. Reynolds' decomposition and Reynolds' averaging. Homogeneous turbulence. Turbulent shear flows: boundary layers, jets and wakes. Introduction to turbulence modelling: algebraic and transport models. Practice examples with turbulent flow data.

Knowledge:

After completion of this course, the student will have knowledge on:

• Basic laws in fluid mechanics.
• Cartesian tensor notation.
• Dimensionless equations, Reynolds number, scales for length and time.
• Vorticity and elements of vortex dynamics.
• Characteristics of turbulence including the scales within it.
• Reynolds’ decomposition, Reynolds-averaged Navier-Stokes equations (RANS).
• Balance equations for the mean flow and the turbulent kinetic energy.
• Turbulence near solid surfaces. The mean velocity profile. Boundary layer equations.
• Free turbulent shear flows. Simplified momentum equations. Self-preservation.
• Turbulence modelling. Eddy viscosity, mixing-length, Reynolds stress models.
• Statistical description of turbulence: moments, correlations, spectra.
• The concepts of direct numerical simulation (DNS) and large-eddy simulation (LES).

Skills:

After completion of this course, the student will have skills on:

• Evaluation of turbulent flow situations.
• Use of self-preservation solutions for free shear flows (jets, wakes, etc).
• Choose a turbulence model for computational flow analysis (CFD).
• Evaluate and interpret experimental measurements.

General competence:

After completion of this course, the student will have general competence on:

• The theory of turbulence and the turbulent flow of liquids and gases (fluids).
• An understanding of turbulent flow cases.

Lectures, written exercises, a CFD project and a laboratory exercise. The lectures and course activities are in English. The exam will be given in English only. Students are free to choose Norwegian or English for written assessments.